S band

S band Frequency range 2–4 GHz

ITU Radio Band Numbers 1 2 3 4 5 6 7 8 9 10 11 12 ITU Radio Band Symbols ELF SLF ULF VLF LF MF HF VHF UHF SHF EHF THF NATO Radio bands A B C D E F G H I J K L M IEEE Radar bands HF VHF UHF L S C X Ku K Ka Q V W D

The S band is part of the microwave band of the electromagnetic spectrum. It is defined by an IEEE standard for radio waves with frequencies that range from 2 to 4 GHz, crossing the conventional boundary between UHF and SHF at 3.0 GHz. The S band is used by weather radar, surface ship radar, and some communications satellites, especially those used by NASA to communicate with the Space Shuttle and the International Space Station. The 10-cm radar short-band ranges roughly from 1.55 to 5.2 GHz.

Satellite communications

In the U.S., the FCC approved Digital Audio Radio Satellite (DARS) broadcasts in the S band from 2.31 to 2.36 GHz, currently used by Sirius XM Radio. More recently, it has approved for portions of the S band between 2.0 and 2.2 GHz the creation of Mobile Satellite Service (MSS) networks in connection with Ancillary Terrestrial Components (ATC). There are presently a number of companies attempting to deploy such networks, including ICO Satellite Management and TerreStar.

The 2.6 GHz range is used for China Multimedia Mobile Broadcasting, a satellite radio and mobile TV standard which, as with proprietary systems in the U.S., is incompatible with the open standards used in the rest of the world.

In May 2009, Inmarsat and Solaris Mobile (a joint venture between Eutelsat and Astra) were awarded each a 2×15 MHz portion of the S band by the European Commission. The two companies are allowed two years to start providing pan-European MSS services for 18 years. Allocated frequencies are 1.98 to 2.01 GHz for Earth to space communications, and from 2.17 to 2.2 GHz for space to Earth communications. Eutelsat W2A satellite launched in April, 2009 and located at 10° East is currently the unique satellite in Europe operating on S band frequencies.

In some countries, S band is used for Direct-to-Home satellite television (unlike similar services in most countries, which use K_u band). The frequency typically allocated for this service is 2.5 to 2.7 GHz (LOF 1.570 GHz).

Other uses

Wireless network equipment compatible with IEEE 802.11b and 802.11g standards use the 2.4 GHz section of the S band. Digital cordless telephones operate in this band too. Microwave ovens operate at 2495 or 2450 MHz. IEEE 802.16a and 802.16e standards utilize a part of the frequency range of S band, under WiMAX standards most vendors are now manufacturing equipment in the range of 3.5 GHz. The exact frequency range allocated for this type of use varies between countries.

In North America, 2.4 - 2.483 GHz is an ISM band used for unlicensed spectrum devices such as cordless phones, wireless headphones, and video senders, among other consumer electronics uses, including Bluetooth which operates between 2.402 GHz and 2.480 GHz.

Amateur radio and amateur satellite operators have two S-band allocations, 13 cm (2.4 GHz) and 9 cm (3.4 GHz).

Optical communications S band

S band is also used in optical communications to refer to the wavelength range 1460 nm to 1530 nm.

Other microwave bands

The microwave spectrum is usually defined as electromagnetic energy ranging from approximately 1 GHz to 100 GHz in frequency, but older usage includes lower frequencies. Most common applications are within the 1 to 40 GHz range. Microwave frequency bands, as defined by the Radio Society of Great Britain (RSGB), are shown in the table below:

L band	1 to 2 GHz
S band	2 to 4 GHz
C band	4 to 8 GHz
X band	8 to 12 GHz
Ku band	12 to 18 GHz
K band	18 to 26.5 GHz
Ka band	26.5 to 40 GHz
Q band	30 to 50 GHz
U band	40 to 60 GHz
V band	50 to 75 GHz
E band	60 to 90 GHz
W band	75 to 110 GHz
F band	90 to 140 GHz
D band	110 to 170 GHz

Footnote: P band is sometimes incorrectly used for Ku Band. "P" for "previous" was a radar band used in the UK ranging from 250 to 500 MHz and now obsolete per IEEE Std 521, see [1] and [2]. For other definitions see Letter Designations of Microwave Bands

See also

• Electromagnetic interference at 2.4 GHz
• ISM band
• Unified S-Band System, an S Band communication system used in the Apollo program of manned spaceflight.
• SafeTRIP an R&D project co-funded by the European Commission for a vehicular open-platform for safety and infotainment services based on S-band communication.

External links

• TerreStar Networks (Nasdaq: TSTR)
• zarya.info - S-band satellite telemetry and housekeeping frequencies
• utexas.edu - Pioneer 10 & 11 Abstract